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The author and publisher have taken care in the preparation of this book, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of the use of the information or programs contained herein.

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美国国会图书馆在编目数据：

Library of Congress Cataloging-in-Publication Data:

拉曼，克雷格。

    应用 UML 和模式：面向对象的分析和设计以及

    迭代开发简介 / Craig Larman。第三版。

        p. 厘米。

        包括参考书目和索引。

        ISBN 0-13-148906-2（alk. paper）

        1. 面向对象的方法（计算机科学） 2. UML（计算机科学） 3. 系统分析

    。4.系统设计。一、标题。



    QA76.9.O35 L37 2004

    005.1'17--dc22 2004057647

Larman, Craig.

    Applying UML and patterns: an introduction to object-oriented analysis and design and

    iterative development / Craig Larman. 3rd ed.

        p. cm.

        Includes bibliographical references and index.

        ISBN 0-13-148906-2 (alk. paper)

        1. Object-oriented methods (Computer science) 2. UML (Computer science) 3. System

    analysis. 4. System design. I. Title.



    QA76.9.O35 L37 2004

    005.1'17--dc22                                                            2004057647

版权所有 © 2005 Pearson Education, Inc.

Copyright © 2005 Pearson Education, Inc.

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All products or services mentioned in this book are the trademarks or service marks of their respective companies or organizations.

引用致谢：

Quote acknowledgments:

Paul Erdos：来自 Paul Hoffman 的“The Man Who Only Loved Numbers”。

HG Wells：经 AP Watt Ltd. 许可代表 HG Wells 遗产执行人使用。

Paul Erdos: From "The Man Who Only Loved Numbers" by Paul Hoffman.

H.G. Wells: Used by permission of A.P. Watt Ltd. On behalf of the Executors of the Estate of H.G. Wells.

在美国马萨诸塞州韦斯特福德的 Courier 使用再生纸印刷的文本

Text printed in the United States on recycled paper at Courier in Westford, Massachusetts

第一次印刷，2004 年 10 月

First printing, October 2004

奉献精神

Dedication

为了朱莉、海莉和汉娜

For Julie, Haley, and Hannah

感谢您的喜爱和支持。

Thanks for the love and support.

赞扬应用 UML 和模式

Praise for Applying UML and Patterns

“这一版包含了拉曼一贯的准确和深思熟虑的写作。这是一本更好的书。”

Alistair Cockburn，作者，Writing Effective Use Cases and Surviving OO Projects

"This edition contains Larman's usual accurate and thoughtful writing. It is a very good book made even better."

Alistair Cockburn, author, Writing Effective Use Cases and Surviving OO Projects

“人们经常问我，哪一本书是向他们介绍 OO 设计世界的最佳书籍。自从我接触到这本书以来，Applying UML and Patterns一直是我毫无保留的选择。”

Martin Fowler，UML 提炼和重构作者

"People often ask me which is the best book to introduce them to the world of OO design. Ever since I came across it Applying UML and Patterns has been my unreserved choice."

Martin Fowler, author, UML Distilled and Refactoring

“这本书通过逐步将 UML 作为一种直观的语言介绍给对象分析和设计的工件，从而使学习 UML 变得有趣和实用。这是一本由专家从业者编写的对 UML 和对象方法的精心介绍。”

Cris Kobryn ， UML修订工作组和UML 2.0 工作组主席

"This book makes learning UML enjoyable and pragmatic by incrementally introducing it as an intuitive language for specifying the artifacts of object analysis and design. It is a well written introduction to UML and object methods by an expert practitioner."

Cris Kobryn, Chair of the UML Revision Task Force and UML 2.0 Working Group

“能解释事物的人太少了。掌握软件分析和设计的人更少。Craig Larman 两者兼具。”

John Vlissides，作者，设计模式和模式孵化

"Too few people have a knack for explaining things. Fewer still have a handle on software analysis and design. Craig Larman has both."

John Vlissides, author, Design Patterns and Pattern Hatching

主要主题目录

Contents by Major Topics

本书逐步介绍了一个主题，随着案例研究的展开而展开。这很有用，但它引入了一个问题：如何找到关于主要主题（例如，OO 设计）的大部分材料？索引是一种解决方案，但是是细粒度的；此清单提供了另一个。

This book introduces a topic incrementally, spread out over chapters as the case studies unfold. That's useful, but it introduces a problem: How can you find most material on a major subject (e.g., OO Design)? The Index is one solution, but fine-grained; this listing provides another.

敏捷实践

Agile Practices

什么是敏捷建模？30

What is Agile Modeling? 30

什么是敏捷 UP？31

What is an Agile UP? 31

敏捷建模和轻量级 UML 绘图214

Agile Modeling and Lightweight UML Drawing 214

有关迭代开发和敏捷项目管理的更多信息673

More on Iterative Development and Agile Project Management 673

建筑学

Architecture

逻辑架构和 UML 包图197

Logical Architecture and UML Package Diagrams 197

建筑分析541

Architectural Analysis 541

逻辑架构细化559

Logical Architecture Refinement 559

包装设计613

Package Design 613

记录架构：UML 和 N+1 视图模型655

Documenting Architecture: UML & the N+1 View Model 655

领域建模

Domain Modeling

领域模型131

Domain Models 131

领域层和领域模型有什么关系？206

What's the Relationship Between the Domain Layer and Domain Model? 206

领域模型细化507

Domain Model Refinement 507

抓牢

GRASP

GRASP：设计具有职责的对象271

GRASP: Designing Objects with Responsibilities 271

GRASP：更多有责任的对象413

GRASP: More Objects with Responsibilities 413

使用多态处理支付并自己动手600

Handling Payments with Polymorphism and Do It Myself 600

示例：大富翁607

Example: Monopoly 607

GoF 设计模式

GoF Design Patterns

什么是模式？278

What are Patterns? 278

应用 GoF 设计模式435

Applying GoF Design Patterns 435

使用 GoF 模式进行更多对象设计579

More Object Design with GoF Patterns 579

使用模式设计持久性框架625

Designing a Persistence Framework with Patterns 625

迭代开发

Iterative Development

迭代、进化和敏捷17

Iterative, Evolutionary, and Agile 17

进化要求53

Evolutionary Requirements 53

迭代 1 基础知识123

Iteration 1Basics 123

迭代设计的要求195

Requirements to DesignIteratively 195

有关迭代开发和敏捷项目管理的更多信息673

More on Iterative Development and Agile Project Management 673

面向对象 分析

OO Analysis

请参见域建模和操作契约

See Domain Modeling and Operation Contracts

面向对象 设计

OO Design

请参阅GRASP 和 GoF 设计模式

See GRASP and GoF Design Patterns

对象设计213

On to Object Design 213

包装设计613

Package Design 613

营运合约

Operation Contracts

经营合同181

Operation Contracts 181

操作合同和用例实现326

Operation Contracts and Use Case Realizations 326

更多 SSD 和合约501

More SSDs and Contracts 501

图案

Patterns

请参阅GRASP 和 GoF 设计模式

See GRASP and GoF Design Patterns

什么是模式？278

What are Patterns? 278

编程

Programming

将设计映射到 Code 369

Mapping Designs to Code 369

测试驱动开发和重构385

Test-Driven Development and Refactoring 385

项目管理

Project Management

参见敏捷实践和迭代开发

See Agile Practices and Iterative Development

有关迭代开发和敏捷项目管理的更多信息673

More on Iterative Development and Agile Project Management 673

要求

Requirements

查看用例

See Use Cases

进化要求53

Evolutionary Requirements 53

其他要求101

Other Requirements 101

迭代设计的要求195

Requirements to DesignIteratively 195

UML 活动图和建模477

UML Activity Diagrams and Modeling 477

UML 状态机图和建模485

UML State Machine Diagrams and Modeling 485

系统顺序指令

System Sequence Dgms

系统时序图173

System Sequence Diagrams 173

SSD、系统操作、交互图和用例实现324

SSDs, System Operations, Interaction Diagrams, and Use Case Realizations 324

更多 SSD 和合约501

More SSDs and Contracts 501

测试

Testing

测试驱动开发和重构385

Test-Driven Development and Refactoring 385

统一语言

UML

什么是UML？11

What is the UML? 11

应用 UML：用例图89

Applying UML: Use Case Diagrams 89

领域模型131

Domain Models 131

应用 UML：序列图177

Applying UML: Sequence Diagrams 177

应用 UML：包图201

Applying UML: Package Diagrams 201

UML 交互图221

UML Interaction Diagrams 221

UML 类图249

UML Class Diagrams 249

UML 活动图和建模477

UML Activity Diagrams and Modeling 477

UML 状态机图和建模485

UML State Machine Diagrams and Modeling 485

用例图499

Use Case Diagrams 499

UML 部署和组件图621

UML Deployment and Component Diagrams 621

统一流程

Unified Process

什么是敏捷 UP？31

What is an Agile UP? 31

还有其他关键的 UP 实践吗？33

Are There Other Critical UP Practices? 33

有关迭代开发和敏捷项目管理的更多信息673

More on Iterative Development and Agile Project Management 673

用例

Use Cases

用例61

Use Cases 61

SSD 和用例之间的关系是什么？177

What is the Relationship Between SSDs and Use Cases? 177

什么是用例实现？322

What is a Use Case Realization? 322

相关用例493

Relating Use Cases 493

如何用用例和场景规划迭代？676

How to Plan Iterations with Use Cases and Scenarios? 676

前言

Foreword

编程很有趣，但开发高质量的软件很难。在好的想法、需求或“愿景”和一个可用的软件产品之间，除了编程之外还有更多的东西。分析和设计，定义如何解决问题，编程什么，以易于交流、审查、实施和发展的方式捕捉这种设计是本书的核心。这就是你将学到的。

Programming is fun, but developing quality software is hard. In between the nice ideas, the requirements or the "vision," and a working software product, there is much more than programming. Analysis and design, defining how to solve the problem, what to program, capturing this design in ways that are easy to communicate, to review, to implement, and to evolve is what lies at the core of this book. This is what you will learn.

统一建模语言 (UML) 已成为普遍接受的软件设计蓝图语言。UML 是贯穿本书的用于传达设计理念的可视化语言，它强调开发人员如何真正应用常用的 UML 元素，而不是语言的晦涩特性。

The Unified Modeling Language (UML) has become the universally-accepted language for software design blueprints. UML is the visual language used to convey design ideas throughout this book, which emphasizes how developers really apply frequently used UML elements, rather than obscure features of the language.

其他学科早已认识到模式在构建复杂系统中的重要性。软件设计模式使我们能够描述设计片段，重用设计思想，帮助开发人员利用他人的专业知识。模式为面向对象技术的抽象启发式方法、规则和最佳实践提供了名称和形式。没有一个通情达理的工程师愿意从一张白纸开始，本书提供了一系列易于使用的设计模式。

The importance of patterns in crafting complex systems has long been recognized in other disciplines. Software design patterns are what allow us to describe design fragments, and reuse design ideas, helping developers leverage the expertise of others. Patterns give a name and form to abstract heuristics, rules and best practices of object-oriented techniques. No reasonable engineer wants to start from a blank slate, and this book offers a palette of readily usable design patterns.

但是，如果不在软件工程过程的上下文中呈现，软件设计看起来有点枯燥和神秘。关于这个话题，我很高兴 Craig Larman 在他的新版本中选择接受和介绍统一过程，展示如何以相对简单和低调的方式应用它。通过在一个迭代的、风险驱动的、以架构为中心的过程中展示案例研究，Craig 的建议具有现实的背景；他揭示了软件开发中真正发生的动态，并展示了外部力量的作用。设计活动与其他任务相关联，它们不再表现为系统转换或创造性直觉的纯粹大脑活动。Craig 和我都相信迭代开发的好处，你会在本书中看到大量的例证。

But software design looks a bit dry and mysterious when not presented in the context of a software engineering process. And on this topic, I am delighted that for his new edition, Craig Larman has chosen to embrace and introduce the Unified Process, showing how it can be applied in a relatively simple and low-ceremony way. By presenting the case study in an iterative, risk-driven, architecture-centric process, Craig's advice has realistic context; he exposes the dynamics of what really happens in software development, and shows the external forces at play. The design activities are connected to other tasks, and they no longer appear as a purely cerebral activity of systematic transformations or creative intuition. And Craig and I are convinced of the benefits of iterative development, which you will see abundantly illustrated throughout.

所以对我来说，这本书的成分组合恰到好处。您将从一位伟大的老师、一位杰出的方法学家和一位向世界各地数以千计的人教授它的“OO 大师”那里学习一种系统的方法来进行面向对象的分析和设计 (OOA/D)。Craig 在统一过程的上下文中描述了该方法。他逐渐呈现出更复杂的设计模式，这将使本书在您面临现实世界的设计挑战时非常得心应手。他使用最广泛接受的符号。

So for me, this book has the right mix of ingredients. You will learn a systematic method to do Object-Oriented Analysis and Design (OOA/D) from a great teacher, a brilliant methodologist, and an "OO guru" who has taught it to thousands around the world. Craig describes the method in the context of the Unified Process. He gradually presents more sophisticated design patternsthis will make the book very handy when you are faced with real-world design challenges. And he uses the most widely accepted notation.

我很荣幸有机会直接与这本重要著作的作者一起工作。我喜欢阅读第一版，当他让我审阅他的新版草稿时我很高兴。我们见过几次面，交换了很多电子邮件。我从 Craig 那里学到了很多东西，甚至是关于我们自己在统一流程方面的流程工作以及如何改进它以及如何在各种组织环境中定位它。我敢肯定，即使您已经熟悉 OOA/D，阅读本书也会学到很多东西。而且，像我一样，您会发现自己会回过头来重温您的记忆，或者从 Craig 的解释和经验中获得进一步的见解。

I'm honored to have had the opportunity to work directly with the author of this major book. I enjoyed reading the first edition, and was delighted when he asked me to review the draft of his new edition. We met several times and exchanged many e-mails. I have learned much from Craig, even about our own process work on the Unified Process and how to improve it and position it in various organizational contexts. I am certain that you will learn a lot, too, in reading this book, even if you are already familiar with OOA/D. And, like me, you will find yourself going back to it, to refresh your memory, or to gain further insights from Craig's explanations and experience.

阅读愉快！

Happy reading!

Philippe Kruchten 不列颠

哥伦比亚大学软件工程教授，



曾任RUP Rational Software

Rational Fellow 和过程开发总监 ，不列颠哥伦比亚省温哥华

Philippe Kruchten

Professor of Software Engineering, University of British Columbia



formerly,

Rational Fellow and Director of Process Development for the RUP

Rational Software

Vancouver, British Columbia

前言

Preface

感谢您阅读本书！如果我可以回答问题，或者咨询或指导团队（在 OOA/D、UML、建模、迭代和敏捷方法方面），请通过 www.craiglarman.com 与我联系。

Thank you for reading this book! If I can answer a question, or for consulting or coaching a team (in OOA/D, UML, modeling, iterative and agile methods) please contact me at www.craiglarman.com.

这是对面向对象分析和设计 (OOA/D) 以及迭代开发相关方面的实用介绍。我很感激以前的版本在世界范围内非常受欢迎。衷心感谢所有读者！

This is a practical introduction to object-oriented analysis and design (OOA/D), and to related aspects of iterative development. I am grateful that the previous editions were extremely popular worldwide. I sincerely thank all the readers!

这本书将如何使您受益。

Here is how the book will benefit you.

首先，对象技术的使用非常广泛，因此掌握 OOA/D 对于您在软件世界取得成功至关重要。

First, the use of object technology is widespread, so mastery of OOA/D is critical for you to succeed in the software world.

其次，如果您是 OOA/D 的新手，您会在如何进行方面遇到挑战，这是可以理解的；本书展示了一个定义明确的迭代路线图和统一过程的敏捷方法，以便您可以逐步从需求到代码的过程。

Second, if you are new to OOA/D, you're understandably challenged about how to proceed; this book presents a well-defined iterative roadmapan agile approach to the Unified Processso that you can move in a step-by-step process from requirements to code.

第三，统一建模语言（Unified Modeling Language，UML）已经成为建模的标准符号，因此能够熟练地应用它是很有用的。

Third, the Unified Modeling Language (UML) has emerged as the standard notation for modeling, so it's useful to be able to apply it skillfully.

第四，设计模式传达了 OO 设计专家应用的“最佳实践”习语。您将学习应用设计模式，包括流行的“四人组”模式和 GRASP 模式。学习和应用模式将加速您对分析和设计的掌握。

Fourth, design patterns communicate the "best practice" idioms OO design experts apply. You will learn to apply design patterns, including the popular "gang-of-four" patterns, and the GRASP patterns. Learning and applying patterns will accelerate your mastery of analysis and design.

第五，本书的结构和重点是基于多年的 OOA/D 艺术教育和指导经验。它通过提供一种精致、经过验证且有效的方法来学习该主题来反映这种体验，因此您在阅读和学习方面的投资得到了优化。

Fifth, the structure and emphasis in this book are based on years of experience in education and mentoring thousands of people in the art of OOA/D. It reflects that experience by providing a refined, proven, and efficient approach to learning the subject, so your investment in reading and learning is optimized.

第六，它详尽地检查了两个案例研究，以真实地说明整个 OOA/D 过程，并深入到问题的棘手细节。

Sixth, it exhaustively examines two case studiesto realistically illustrate the entire OOA/D process, and goes deeply into thorny details of the problem.

第七，它展示了如何将对象设计工件映射到 Java 代码。它还介绍了测试驱动开发和重构。

Seventh, it shows how to map object design artifacts to code in Java. It also introduces test-driven development and refactor.

第八，它解释了如何设计分层架构并将 UI 层与领域和技术服务层相关联。

Eighth, it explains how to design a layered architecture and relate the UI layer to domain and technical services layers.

最后，它向您展示了如何设计 OO 框架并将其应用于创建数据库中持久存储的框架。

Finally, it shows you how to design an OO framework and applies this to the creation of a framework for persistent storage in a database.

教育工作者和网络资源

Educator and Web Resources

您可以在www.craiglarman.com上找到感兴趣的相关文章。

You may find related articles of interest at www.craiglarman.com.

全世界有数百（如果不是数千）教师使用这本书；它已被翻译成至少十种语言。在我的网站上有各种教育资源，包括组织成 Microsoft PowerPoint 演示文稿的所有书籍插图、示例 OOA/D PowerPoint 演示文稿等。如果您是一名教育工作者，请联系我获取资源。

Hundreds, if not thousands, of teachers use the book worldwide; it's been translated into at least ten languages. At my website there are a variety of educator resources, including all the book figures organized into Microsoft PowerPoint presentations, sample OOA/D PowerPoint presentations, and more. If you're an educator, please contact me for resources.

我正在从现有的使用这本书的教育工作者那里收集资料，与其他教育工作者分享。如果您有任何要分享的内容，请与我联系。

I am collecting material from existing educators using the book, to share with other educators. If you have anything to share, please contact me.

目标观众简介！

Intended Audiencean Introduction!

本书介绍了OOA/D、相关需求分析以及以统一过程为样本过程的迭代开发；它不是高级文本。它适用于以下观众：

This book is an introduction to OOA/D, related requirements analysis, and to iterative development with the Unified Process as a sample process; it is not meant as an advanced text. It is for the following audience:

• 在 OO 编程方面有一些经验，但对 OOA/D 不熟悉或相对较新的开发人员和学生。

• Developers and students with some experience in OO programming, but who are newor relatively newto OOA/D.

• 学习对象技术的计算机科学或软件工程课程的学生。

• Students in computer science or software engineering courses studying object technology.

• 熟悉 OOA/D 并希望学习 UML 符号、应用模式或希望加深分析和设计技能的人员。

• Those with some familiarity in OOA/D who want to learn the UML notation, apply patterns, or who want to deepen their analysis and design skills.

先决条件

Prerequisites

要从本书中获益，需要具备一些先决条件：

Some prerequisites are assumedand necessaryto benefit from this book:

• 具备面向对象编程语言（如 Java、C#、C++ 或 Python）的知识和经验。

• Knowledge and experience in an object-oriented programming language such as Java, C#, C++, or Python.

• 了解基本的 OO 概念，例如类、实例、接口、多态性、封装和继承。

• Knowledge of fundamental OO concepts, such as class, instance, interface, polymorphism, encapsulation, and inheritance.

没有定义基本的 OO 概念。

Fundamental OO concepts are not defined.

Java 示例，但是……

Java Examples, But …

总的来说，由于 Java 广为人知，本书提供了 Java 代码示例。然而，所提出的想法适用于大多数面向对象技术，包括 C#、Python 等。

In general, the book presents code examples in Java due to its widespread familiarity. However, the ideas presented are applicable to mostif not allobject-oriented technologies, including C#, Python, and so on.

书籍组织

Book Organization

本书组织的总体策略是分析和设计主题的介绍顺序类似于软件开发项目在“初始”阶段（统一过程术语）中运行的顺序，然后是三个迭代（见图 P.1）。 1 ).

The overall strategy in the organization of this book is that analysis and design topics are introduced in an order similar to that of a software development project running across an "inception" phase (a Unified Process term) followed by three iterations (see Figure P.1).

图 P.1。本书的组织遵循开发项目的组织。

[查看全尺寸图片]

关于作者

About the Author

Craig Larman 担任 Valtech 的首席科学家，这是一家在欧洲、亚洲和北美设有分部的国际咨询和技能转移公司。他还是畅销软件工程和迭代、敏捷开发书籍《敏捷和迭代开发：经理指南》的作者。他周游世界，从印第安纳州到印度，指导开发团队和经理。

Craig Larman serves as chief scientist for Valtech, an international consulting and skills transfer company with divisions in Europe, Asia, and North America. He is also author of the best-selling software engineering and iterative, agile development text Agile and Iterative Development: A Manager's Guide. He travels worldwide, from Indiana to India, coaching development teams and managers.

自 20 世纪 80 年代中期以来，Craig 已经帮助数以千计的开发人员应用 OOA/D、使用 UML 进行熟练的建模，并采用迭代开发实践。

Since the mid 1980s, Craig has helped thousands of developers to apply OOA/D, skillful modeling with the UML, and to adopt iterative development practices.

在流浪街头音乐家的职业生涯失败后，他在 1970 年代用 APL、PL/I 和 CICS 构建了系统。从 1980 年代初开始，在完全康复后，他开始对人工智能感兴趣（他自己几乎没有），并使用 Lisp 机器、Lisp、Prolog 和 Smalltalk 构建知识系统。他还曾在使用 Java、.NET、C++ 和 Smalltalk 构建业务系统的组织中工作。他在他的兼职乐队Changing Requirements（以前称为Requirements，但一些乐队成员改变了......）中弹奏糟糕的主音吉他。

After a failed career as a wandering street musician, he built systems in APL, PL/I, and CICS in the 1970s. Starting in the early 1980safter a full recovery he became interested in artificial intelligence (having little of his own) and built knowledge systems with Lisp machines, Lisp, Prolog, and Smalltalk. He's also worked in organizations that build business systems in Java, .NET, C++, and Smalltalk. He plays bad lead guitar in his very part-time band, the Changing Requirements (it used to be called the Requirements, but some band members changed...).

他拥有加拿大温哥华美丽的西蒙弗雷泽大学的计算机科学学士和硕士学位。

He holds a B.S. and M.S. in computer science from beautiful Simon Fraser University in Vancouver, Canada.

接触

Contact

可以通过craig@craiglarman.com和www.craiglarman.com联系 Craig 。他欢迎来自读者和教育工作者的提问，以及演讲、指导和咨询查询。

Craig can be reached at craig@craiglarman.com and www.craiglarman.com. He welcomes questions from readers and educators, and speaking, mentoring, and consulting enquiries.

对上一版本的改进

Enhancements to the Previous Edition

在保留与先前版本相同的核心的同时，此版本在许多方面进行了改进，包括：

While retaining the same core as the prior edition, this edition is refined in many ways, including:

• 通用语言2

• UML 2

• 第二个案例研究

• A second case study

• 关于结合 OOA/D 的迭代和进化开发的更多技巧

• More tips on iterative and evolutionary development combined with OOA/D

• 用新的学习辅助工具和图形重写，以便于学习

• Rewritten with new learning aids and graphics for easier study

• 新的大学教师教学资源

• New college-educator teaching resources

• 敏捷建模、测试驱动开发和重构

• Agile Modeling, Test-Driven Development, and refactoring

• 有关使用 UML 活动图进行流程建模的更多信息

• More on process modeling with UML activity diagrams

• 以轻便、敏捷的精神应用 UP 的指南，与其他迭代方法（如 XP 和 Scrum）相辅相成

• Guidance on applying the UP in a light, agile spirit, complementary with other iterative methods such as XP and Scrum

• 将 UML 应用于记录架构

• Applying the UML to documenting architectures

• 进化要求的新篇章

• A new chapter on evolutionary requirements

• 使用非常流行的 [ Cockburn01 ]方法细化用例章节

• Refinement of the use case chapters, using the very popular approach of [Cockburn01]

致谢

Acknowledgments

首先，感谢我在 Valtech 的朋友和同事，世界级的对象开发人员和迭代开发专家，他们以某种方式对本书做出了贡献、支持或审阅，包括 Chris Tarr、Tim Snyder、Curtis Hite、Celso Gonzalez、Pascal Roques 、Ken DeLong、Brett Schuchert、Ashley Johnson、Chris Jones、Thomas Liou、Darryl Gebert，还有很多我想不起来的人。

First, thanks to my friends and colleagues at Valtech, world-class object developers and iterative development experts, who in some way contributed to, supported, or reviewed the book, including Chris Tarr, Tim Snyder, Curtis Hite, Celso Gonzalez, Pascal Roques, Ken DeLong, Brett Schuchert, Ashley Johnson, Chris Jones, Thomas Liou, Darryl Gebert, and many more than I can name.

感谢 Philippe Kruchten，感谢他撰写前言、审阅本书并以多种方式提供帮助。

To Philippe Kruchten for writing the foreword, reviewing, and helping in many ways.

感谢 Martin Fowler 和 Alistair Cockburn，他们就流程和设计、报价和评论进行了许多富有洞察力的讨论。

To Martin Fowler and Alistair Cockburn for many insightful discussions on process and design, quotes, and reviews.

感谢 Oystein Haugen、Cris Kobryn、Jim Rumbaugh 和 Bran Selic 审阅了 UML 2 材料。

To Oystein Haugen, Cris Kobryn, Jim Rumbaugh, and Bran Selic for reviewing the UML 2 material.

感谢 John Vlissides 和 Cris Kobryn 的引用。

To John Vlissides and Cris Kobryn for the kind quotes.

向 Chelsea Systems 和 John Gray 寻求帮助，以解决受其 Java 技术 ChelseaStore POS 系统启发的一些需求。

To Chelsea Systems and John Gray for help with some requirements inspired by their Java technology ChelseaStore POS system.

感谢 Pete Coad 和 Dave Astels 的意见。

To Pete Coad and Dave Astels for their input.

非常感谢其他审稿人，包括 Steve Adolph、Bruce Anderson、Len Bass、Gary K. Evans、Al Goerner、Luke Hohmann、Eric Lefebvre、David Nunn 和 Robert J. White。

Many thanks to the other reviewers, including Steve Adolph, Bruce Anderson, Len Bass, Gary K. Evans, Al Goerner, Luke Hohmann, Eric Lefebvre, David Nunn, and Robert J. White.

感谢 Prentice-Hall 的 Paul Becker 相信第一版将是一个有价值的项目，并感谢 Paul Petralia 指导了后来的版本。

Thanks to Paul Becker at Prentice-Hall for believing the first edition would be a worthwhile project, and to Paul Petralia for shepherding the later ones.

最后，特别感谢 Graham Glass 打开了一扇门。

Finally, a special thanks to Graham Glass for opening a door.

印刷约定

Typographical Conventions

这是一个句子中的新词。这是一句话中的类名或方法名。这是作者参考 [Bob67]。

This is a new term in a sentence. This is a Class or method name in a sentence. This is an author reference [Bob67].

制作说明

Production Notes

该手稿是使用 Adob​​e FrameMaker 创建的。所有绘图均使用 Microsoft Visio 完成。正文字体为新世纪教科书。最终打印图像是使用 Adob​​e Acrobat Distiller 从 Adob​​e Universal 驱动程序生成的 PostScript 生成为 PDF 的。UML 墙面草图照片已使用 ClearBoard 清理干净，用于白板照片。

The manuscript was created with Adobe FrameMaker. All drawings were done with Microsoft Visio. The body font is New Century Schoolbook. The final print images were generated as PDF using Adobe Acrobat Distiller, from PostScript generated by the Adobe Universal driver. The UML wall sketch photos were cleaned up with ClearBoard for whiteboard photos.

第 1 部分：简介

Part 1: Introduction

第 1 章面向对象的分析与设计

Chapter 1.  Object-Oriented Analysis and Design

第 2 章迭代、进化和敏捷

Chapter 2.  Iterative, Evolutionary, and Agile

第 3 章案例研究

Chapter 3.  Case Studies

第 1 章面向对象的分析与设计

Chapter 1. Object-Oriented Analysis and Design

Le temps est un grand professeur, mais malheureusement il tue tous ses élèves（时间是一位伟大的老师，但不幸的是它杀死了所有的学生。）

赫克托·柏辽兹

Le temps est un grand professeur, mais malheureusement il tue tous ses élèves (Time is a great teacher, but unfortunately it kills all its pupils.)

Hector Berlioz

1.1. 你会学到什么？有用吗？

1.1. What Will You Learn? Is it Useful?

拥有良好的对象设计意味着什么？本书是帮助开发人员和学生学习面向对象分析与设计 (OOA/D) 核心技能的工具。这些技能对于使用 OO 技术和语言（如 Java 或 C#）创建设计良好、健壮且可维护的软件至关重要。

What does it mean to have a good object design? This book is a tool to help developers and students learn core skills in object-oriented analysis and design (OOA/D). These skills are essential for the creation of well-designed, robust, and maintainable software using OO technologies and languages such as Java or C#.

谚语“拥有一把锤子并不能使一个人成为架构师”对于对象技术来说尤其如此。了解面向对象的语言（如 Java）是创建对象系统的必要但不充分的第一步。知道如何“在对象中思考”是至关重要的！

The proverb "owning a hammer doesn't make one an architect" is especially true with respect to object technology. Knowing an object-oriented language (such as Java) is a necessary but insufficient first step to create object systems. Knowing how to "think in objects" is critical!

这是在应用统一建模语言 (UML) 和模式时对 OOA/D 的介绍。并且，为了迭代开发，使用统一过程的敏捷方法作为迭代过程的示例。它不是高级文本；它强调掌握基础知识，例如如何将职责分配给对象、常用的 UML 符号和常见的设计模式。同时，主要是在后面的章节中，材料会发展到一些中级主题，例如框架设计和体系结构分析。

This is an introduction to OOA/D while applying the Unified Modeling Language (UML) and patterns. And, to iterative development, using an agile approach to the Unified Process as an example iterative process. It is not meant as an advanced text; it emphasizes mastery of the fundamentals, such as how to assign responsibilities to objects, frequently used UML notation, and common design patterns. At the same time, mostly in later chapters, the material progresses to some intermediate-level topics, such as framework design and architectural analysis.

UML 与对象思维

UML vs. Thinking in Objects

这本书不仅仅是关于 UML 的。UML是一种标准的图表符号。通用符号很有用，但还有更重要的面向对象的东西需要学习，尤其是如何在对象中思考。UML 不是 OOA/D 或方法，它只是图表符号。学习 UML 和 UML CASE 工具是没有用的，但不知道如何创建出色的 OO 设计，或评估和改进现有设计。这是一项艰巨而重要的技能。因此，本书是对象设计的介绍。

The book is not just about UML. The UML is a standard diagramming notation. Common notation is useful, but there are more important OO things to learn especially, how to think in objects. The UML is not OOA/D or a method, it is just diagramming notation. It's useless to learn UML and perhaps a UML CASE tool, but not really know how to create an excellent OO design, or evaluate and improve an existing one. This is the hard and important skill. Consequently, this book is an introduction to object design.

然而，我们需要一种用于 OOA/D 和“软件蓝图”的语言，既作为一种思维工具，又作为一种交流形式。因此，本书探讨了如何将UML应用到为OOA/D服务中，并涵盖了常用的UML。

Yet, we need a language for OOA/D and "software blueprints," both as a tool of thought and as a form of communication. Therefore, this book explores how to apply the UML in the service of doing OOA/D, and covers frequently used UML.

OOD：原则和模式

OOD: Principles and Patterns

职责应该如何分配给对象类？对象应该如何协作？什么类应该做什么？这些都是系统设计中的关键问题，本书教授经典的 OO 设计隐喻：责任驱动设计。此外，某些经过验证的设计问题解决方案可以（并且已经）表示为最佳实践原则、启发式方法或名为问题解决方案公式的模式，这些公式将示例性设计原则编纂成文。本书通过教授如何应用模式或原则，支持更快地学习和熟练地使用这些基本的对象设计习语。

How should responsibilities be allocated to classes of objects? How should objects collaborate? What classes should do what? These are critical questions in the design of a system, and this book teaches the classic OO design metaphor: responsibility-driven design. Also, certain tried-and-true solutions to design problems can be (and have been) expressed as best-practice principles, heuristics, or patternsnamed problem-solution formulas that codify exemplary design principles. This book, by teaching how to apply patterns or principles, supports quicker learning and skillful use of these fundamental object design idioms.

实例探究

Case Studies

OOA/D 的介绍在一些正在进行的案例研究中得到了说明，这些案例研究贯穿全书，深入到分析和设计中，以便考虑在现实问题中必须考虑和解决的一些血淋淋的细节，并且解决了。

This introduction to OOA/D is illustrated in some ongoing case studies that are followed throughout the book, going deep enough into the analysis and design so that some of the gory details of what must be considered and solved in a realistic problem are considered, and solved.

用例

Use Cases

OOD（以及所有软件设计）与需求分析的先决条件活动密切相关，通常包括编写用例。因此，案例研究从介绍这些主题开始，即使它们不是专门面向对象的。

OOD (and all software design) is strongly related to the prerequisite activity of requirements analysis, which often includes writing use cases. Therefore, the case study begins with an introduction to these topics, even though they are not specifically object-oriented.

迭代开发、敏捷建模和敏捷 UP

Iterative Development, Agile Modeling, and an Agile UP

考虑到从需求到实施的许多可能活动，开发人员或团队应该如何进行？需求分析和 OOA/D 需要在某些开发过程的上下文中呈现和实践。在这种情况下，使用敏捷（轻量、灵活）的方法来实现众所周知的统一过程(UP) 作为示例 迭代开发过程，其中介绍了这些主题。然而，所涵盖的分析和设计主题对于许多方法都是通用的，并且在敏捷 UP 的上下文中学习它们并不会使它们对其他方法的适用性无效，例如 Scrum、特性驱动开发、精益开发、水晶方法、等等。

Given many possible activities from requirements through to implementation, how should a developer or team proceed? Requirements analysis and OOA/D needs to be presented and practiced in the context of some development process. In this case, an agile (light, flexible) approach to the well-known Unified Process (UP) is used as the sample iterative development process within which these topics are introduced. However, the analysis and design topics that are covered are common to many approaches, and learning them in the context of an agile UP does not invalidate their applicability to other methods, such as Scrum, Feature-Driven Development, Lean Development, Crystal Methods, and so on.

许多其他技能也很重要！

Many Other Skills Are Important!

这不是完整的软件手册；它主要是对 OOA/D、UML 和迭代开发的介绍，同时涉及相关主题。构建软件涉及无数其他技能和步骤；例如，可用性工程、用户界面设计和数据库设计是成功的关键。

This isn't the Compleate Booke of Software; it's primarily an introduction to OOA/D, UML, and iterative development, while touching on related subjects. Building software involves myriad other skills and steps; for example, usability engineering, user interface design, and database design are critical to success.

1.2. 最重要的学习目标？

1.2. The Most Important Learning Goal?

在介绍性 OOA/D 中有许多可能的活动和工件，以及大量的原则和指南。假设我们必须从这里讨论的所有主题中选择一项实用技能“荒岛”技能。那会是什么？

There are many possible activities and artifacts in introductory OOA/D, and a wealth of principles and guidelines. Suppose we must choose a single practical skill from all the topics discussed herea "desert island" skill. What would it be?

为什么？因为这是在绘制 UML 图或编程时必须执行的一项活动，并且它强烈影响软件组件的健壮性、可维护性和可重用性。

Why? Because it is one activity that must be performedeither while drawing a UML diagram or programmingand it strongly influences the robustness, maintainability, and reusability of software components.

当然，在 OOA/D 中还有其他重要的技能，但在本简介中强调了责任分配，因为它往往是一项具有挑战性的技能（具有许多“自由度”或备选方案），但又非常重要。在真实项目中，开发人员可能没有机会执行任何其他建模活动——“急于编码”开发过程。然而，即使在这种情况下，分配责任也是不可避免的。

Of course, there are other important skills in OOA/D, but responsibility assignment is emphasized in this introduction because it tends to be a challenging skill to master (with many "degrees of freedom" or alternatives), and yet is vitally important. On a real project, a developer might not have the opportunity to perform any other modeling activitiesthe "rush to code" development process. Yet even in this situation, assigning responsibilities is inevitable.

因此，本书中的设计步骤强调责任分配的原则。

Consequently, the design steps in this book emphasize principles of responsibility assignment.

1.3. 什么是分析与设计？

1.3. What is Analysis and Design?

分析强调对问题和需求的调查，而不是解决方案。例如，如果需要一个新的在线交易系统，将如何使用它？它的功能是什么？

Analysis emphasizes an investigation of the problem and requirements, rather than a solution. For example, if a new online trading system is desired, how will it be used? What are its functions?

“分析”是一个广义的术语，最有资格，如需求分析（对需求的调查）或面向对象的分析（对领域对象的调查）。

"Analysis" is a broad term, best qualified, as in requirements analysis (an investigation of the requirements) or object-oriented analysis (an investigation of the domain objects).

设计强调满足需求的概念性解决方案（软件和硬件），而不是其实施。例如，数据库模式和软件对象的描述。设计理念通常会排除对目标消费者而言显而易见的低级或“显而易见”的细节。最终，设计可以被实现，而实现（如代码）表达了真实完整的实现设计。

Design emphasizes a conceptual solution (in software and hardware) that fulfills the requirements, rather than its implementation. For example, a description of a database schema and software objects. Design ideas often exclude low-level or "obvious" detailsobvious to the intended consumers. Ultimately, designs can be implemented, and the implementation (such as code) expresses the true and complete realized design.

与分析一样，该术语最适合用于面向对象设计或数据库设计。

As with analysis, the term is best qualified, as in object-oriented design or database design.

有用的分析和设计已概括为短语“做正确的事”（分析）和“正确地做事”（设计）。

Useful analysis and design have been summarized in the phrase do the right thing (analysis), and do the thing right (design).

1.4. 什么是面向对象分析与设计？

1.4. What is Object-Oriented Analysis and Design?

在面向对象的分析过程中，重点是查找和描述问题域中的对象或概念。例如，对于航班信息系统，一些概念包括Plane、Flight和Pilot。

During object-oriented analysis there is an emphasis on finding and describing the objectsor conceptsin the problem domain. For example, in the case of the flight information system, some of the concepts include Plane, Flight, and Pilot.

在面向对象设计（或简称为对象设计）期间，重点是定义软件对象以及它们如何协作以满足需求。例如，一个Plane软件对象可能有一个tailNumber属性和一个getFlightHistory方法（见图1.2）。

During object-oriented design (or simply, object design) there is an emphasis on defining software objects and how they collaborate to fulfill the requirements. For example, a Plane software object may have a tailNumber attribute and a getFlightHistory method (see Figure 1.2).

图 1.2。面向对象强调对象的表示。

[查看全尺寸图片]

最后，在实现或面向对象编程期间，实现设计对象，例如Java 中的Plane类。

Finally, during implementation or object-oriented programming, design objects are implemented, such as a Plane class in Java.

1.5. 一个简短的例子 1.5. A Short Example

在深入了解迭代开发、需求分析、UML 和 OOA/D 的细节之前，本节使用一个简单的例子——软件模拟玩家滚动的“骰子游戏”，展示几个关键步骤和图表的鸟瞰图两个骰子。如果总数是七，他们赢了；否则，他们输了。

Before diving into the details of iterative development, requirements analysis, UML, and OOA/D, this section presents a bird's-eye view of a few key steps and diagrams, using a simple examplea "dice game" in which software simulates a player rolling two dice. If the total is seven, they win; otherwise, they lose.

定义用例

Define Use Cases

需求分析可能包括人们如何使用应用程序的故事或场景；这些可以写成用例。

Requirements analysis may include stories or scenarios of how people use the application; these can be written as use cases.

用例不是面向对象的人工制品——它们只是书面故事。但是，它们是需求分析中的流行工具。例如，这是玩骰子游戏用例的简短版本：

Use cases are not an object-oriented artifactthey are simply written stories. However, they are a popular tool in requirements analysis. For example, here is a brief version of the Play a Dice Game use case:

玩骰子游戏： 玩家请求掷骰子。系统给出结果：如果骰子面值总和为七，则玩家获胜；否则，玩家输了。

Play a Dice Game: Player requests to roll the dice. System presents results: If the dice face value totals seven, player wins; otherwise, player loses.

定义领域模型

Define a Domain Model

面向对象分析关注于从对象的角度创建对域的描述。对被认为值得注意的概念、属性和关联进行了标识。

Object-oriented analysis is concerned with creating a description of the domain from the perspective of objects. There is an identification of the concepts, attributes, and associations that are considered noteworthy.

结果可以在显示值得注意的领域概念或对象的领域模型中表达。

The result can be expressed in a domain model that shows the noteworthy domain concepts or objects.

例如，部分域模型如图1.3所示。

For example, a partial domain model is shown in Figure 1.3.

此模型说明了值得注意的概念Player、Die和DiceGame及其关联和属性。

This model illustrates the noteworthy concepts Player, Die, and DiceGame, with their associations and attributes.

请注意，领域模型不是软件对象的描述；它是现实世界领域的概念或心智模型的可视化。因此，它也被称为概念对象模型。

Note that a domain model is not a description of software objects; it is a visualization of the concepts or mental models of a real-world domain. Thus, it has also been called a conceptual object model.

分配对象职责并绘制交互图

Assign Object Responsibilities and Draw Interaction Diagrams

面向对象的设计关注于定义软件对象、它们的职责和协作。说明这些协作的常用符号是序列图（一种 UML 交互图）。它显示了软件对象之间的消息流，以及方法的调用。

Object-oriented design is concerned with defining software objectstheir responsibilities and collaborations. A common notation to illustrate these collaborations is the sequence diagram (a kind of UML interaction diagram). It shows the flow of messages between software objects, and thus the invocation of methods.

例如，图 1.4中的序列图通过向DiceGame和Die类的实例发送消息来说明 OO 软件设计。请注意，这说明了应用 UML 的一种常见的现实世界方式：通过在白板上绘制草图。

For example, the sequence diagram in Figure 1.4 illustrates an OO software design, by sending messages to instances of the DiceGame and Die classes. Note this illustrates a common real-world way the UML is applied: by sketching on a whiteboard.

请注意，虽然在现实世界中玩家掷骰子，但在软件设计中DiceGame对象“掷”骰子（即向Die对象发送消息）。软件对象设计和程序确实从现实世界领域中汲取了一些灵感，但它们不是现实世界的直接模型或模拟。

Notice that although in the real world a player rolls the dice, in the software design the DiceGame object "rolls" the dice (that is, sends messages to Die objects). Software object designs and programs do take some inspiration from real-world domains, but they are not direct models or simulations of the real world.

定义设计类图

Define Design Class Diagrams

除了交互图中显示的协作对象的动态视图之外，类定义的静态视图也很有用地与设计类图一起显示。这说明了类的属性和方法。

In addition to a dynamic view of collaborating objects shown in interaction diagrams, a static view of the class definitions is usefully shown with a design class diagram. This illustrates the attributes and methods of the classes.

例如，在骰子游戏中，检查序列图会得出图 1.5所示的部分设计类图。由于播放消息被发送到DiceGame对象，因此DiceGame类需要一个play方法，而类Die需要一个roll和getFaceValue方法。

For example, in the dice game, an inspection of the sequence diagram leads to the partial design class diagram shown in Figure 1.5. Since a play message is sent to a DiceGame object, the DiceGame class requires a play method, while class Die requires a roll and getFaceValue method.

与显示真实世界类的域模型相反，此图显示软件类。

In contrast to the domain model showing real-world classes, this diagram shows software classes.

请注意，虽然这个设计类图与领域模型不一样，但有些类名和内容是相似的。通过这种方式，面向对象的设计和语言可以支持软件组件和我们的领域心智模型之间更小的表征差距。这样可以提高理解力。

Notice that although this design class diagram is not the same as the domain model, some class names and content are similar. In this way, OO designs and languages can support a lower representational gap between the software components and our mental models of a domain. That improves comprehension.

概括

Summary

骰子游戏是一个简单的问题，提出来侧重于分析和设计中的几个步骤和工件。为了简单起见，并未解释所有图示的 UML 符号。以后的章节将更详细地探讨分析和设计以及这些工件。

The dice game is a simple problem, presented to focus on a few steps and artifacts in analysis and design. To keep the introduction simple, not all the illustrated UML notation was explained. Future chapters explore analysis and design and these artifacts in closer detail.

1.6. 什么是UML？

1.6. What is the UML?

去引用：

To quote:

统一建模语言是一种可视化语言，用于指定、构建和记录系统工件 [ OMG03a ]。

The Unified Modeling Language is a visual language for specifying, constructing and documenting the artifacts of systems [OMG03a].

定义中的“视觉”一词是一个关键点——UML 是事实上的标准图表符号，用于绘制或展示与软件（主要是 OO 软件）相关的图片（带有一些文本）。

The word visual in the definition is a key pointthe UML is the de facto standard diagramming notation for drawing or presenting pictures (with some text) related to softwareprimarily OO software.

本书并未涵盖 UML 的所有细节，这是一个庞大的符号体系。它侧重于经常使用的图表、其中最常用的特性，以及在未来的 UML 版本中不太可能改变的核心符号。

This book doesn't cover all minute aspects of the UML, a large body of notation. It focuses on frequently used diagrams, the most commonly used features within those, and core notation that is unlikely to change in future UML versions.

UML 定义了各种UML 配置文件，这些配置文件专门用于常见主题领域的符号子集，例如图表化 Enterprise JavaBeans（使用UML EJB 配置文件）。

The UML defines various UML profiles that specialize subsets of the notation for common subject areas, such as diagramming Enterprise JavaBeans (with the UML EJB profile).

在更深层次上，模型驱动架构(MDA) CASE 工具供应商主要感兴趣的是 UML 符号下的 UML元 模型，它描述了建模元素的语义。这不是开发人员需要学习的东西。

At a deeper levelprimarily of interest to Model Driven Architecture (MDA) CASE tool vendorsunderlying the UML notation is the UML meta-model that describes the semantics of the modeling elements. It isn't something a developer needs to learn.

应用 UML 的三种方法

Three Ways to Apply UML

在 [ Fowler03 ] 中介绍了人们应用 UML 的三种方式：

In [Fowler03] three ways people apply UML are introduced:

• UML as sketch 非正式和不完整的图表（通常在白板上手绘）创建用于探索问题或解决方案空间的困难部分，利用视觉语言的力量。

• UML as sketch Informal and incomplete diagrams (often hand sketched on whiteboards) created to explore difficult parts of the problem or solution space, exploiting the power of visual languages.

• UML 作为蓝图 相对详细的设计图用于 1) 逆向工程以可视化和更好地理解 UML 图中的现有代码，或用于 2) 代码生成（正向工程）。

• UML as blueprint Relatively detailed design diagrams used either for 1) reverse engineering to visualize and better understanding existing code in UML diagrams, or for 2) code generation (forward engineering).

• UML 和“银弹”思维 弗雷德里克·布鲁克斯博士在 1986 年有一篇名为“没有银弹”的著名论文，也发表在他的经典著作《人月神话》 （20周年纪念版）中。推荐阅读！重要的一点是，认为软件中有某种特殊工具或技术可以在生产率、缺陷减少、可靠性或简单性方面产生显着数量级的差异，这是一个根本错误（到目前为止，无休止地重复）。工具并不能弥补设计上的无知。 然而，您通常会听到工具供应商声称绘制 UML 图会使事情变得更好；或者，基于 UML 的模型驱动架构 (MDA) 工具将成为突破性的灵丹妙药。 现实检查时间。UML 只是一个标准的图表符号框、线条等。使用通用符号的可视化建模可能是一个很好的帮助，但它并不像知道如何在对象中设计和思考那么重要。这种设计知识是一种非常不同且更重要的技能，不是通过学习 UML 符号或使用 CASE 或 MDA 工具来掌握的。没有良好的 OO 设计和编程技能的人绘制 UML 只是在绘制糟糕的设计。我推荐文章Death by UML Fever [ Bell04 ]（由 UML 创建者 Grady Booch 认可）以了解更多关于这个主题的信息，以及UML 是什么和不是什么[ Larman04 ]。 因此，本书是对 OOA/D 和应用UML 来支持熟练的 OO 设计的介绍。

  
  
  

  • 如果进行逆向工程，UML 工具会读取源代码或二进制文件并生成（通常）UML 包、类和序列图。这些“蓝图”可以帮助读者理解全局元素、结构和协作。

  • 在编程之前，一些详细的图表可以为代码生成（例如，在 Java 中）提供指导，可以手动或使用工具自动生成。图表通常用于某些代码，而其他代码由开发人员在编码时填写（可能还应用 UML 草图）。

• UML and "Silver Bullet" Thinking There is a well-known paper from 1986 titled "No Silver Bullet" by Dr. Frederick Brooks, also published in his classic book Mythical Man-Month (20th anniversary edition). Recommended reading! An essential point is that it's a fundamental mistake (so far, endlessly repeated) to believe there is some special tool or technique in software that will make a dramatic order-of-magnitude difference in productivity, defect reduction, reliability, or simplicity. And tools don't compensate for design ignorance. Yet, you will hear claimsusually from tool vendorsthat drawing UML diagrams will make things much better; or, that Model Driven Architecture (MDA) tools based on UML will be the breakthrough silver bullet. Reality-check time. The UML is simply a standard diagramming notationboxes, lines, etc. Visual modeling with a common notation can be a great aid, but it is hardly as important as knowing how to design and think in objects. Such design knowledge is a very different and more important skill, and is not mastered by learning UML notation or using a CASE or MDA tool. A person not having good OO design and programming skills who draws UML is just drawing bad designs. I suggest the article Death by UML Fever [Bell04] (endorsed by the UML creator Grady Booch) for more on this subject, and also What UML Is and Isn't [Larman04]. Therefore, this book is an introduction to OOA/D and applying the UML to support skillful OO design.

  
  
  

  • If reverse engineering, a UML tool reads the source or binaries and generates (typically) UML package, class, and sequence diagrams. These "blueprints" can help the reader understand the big-picture elements, structure, and collaborations.

  • Before programming, some detailed diagrams can provide guidance for code generation (e.g., in Java), either manually or automatically with a tool. It's common that the diagrams are used for some code, and other code is filled in by a developer while coding (perhaps also applying UML sketching).

• UML 作为编程语言 UML 中软件系统的完整可执行规范。可执行代码将自动生成，但通常不会被开发人员看到或修改；一种仅适用于 UML“编程语言”。UML 的这种使用需要一种实用的方法来绘制所有行为或逻辑图（可能使用交互图或状态图），并且在理论、工具稳健性和可用性方面仍在开发中。

• UML as programming language Complete executable specification of a software system in UML. Executable code will be automatically generated, but is not normally seen or modified by developers; one works only in the UML "programming language." This use of UML requires a practical way to diagram all behavior or logic (probably using interaction or state diagrams), and is still under development in terms of theory, tool robustness and usability.

敏捷建模强调UML as sketch；这是应用 UML 的常用方法，通常具有很高的时间投资回报率（通常时间很短）。UML 工具可能很有用，但我鼓励人们也考虑使用敏捷建模方法来应用 UML。

Agile modeling emphasizes UML as sketch; this is a common way to apply the UML, often with a high return on the investment of time (which is typically short). UML tools can be useful, but I encourage people to also consider an agile modeling approach to applying UML.

应用UML的三个视角

Three Perspectives to Apply UML

UML 描述原始图类型，例如类图和序列图。它不会在这些之上叠加建模视角。例如，相同的 UML 类图表示法可用于绘制现实世界中的概念图或 Java 中的软件类图。

The UML describes raw diagram types, such as class diagrams and sequence diagrams. It does not superimpose a modeling perspective on these. For example, the same UML class diagram notation can be used to draw pictures of concepts in the real world or software classes in Java.

Syntropy 面向对象方法 [ CD94 ] 强调了这种洞察力。也就是说，相同的符号可用于三种视角和模型类型（图 1.6）：

This insight was emphasized in the Syntropy object-oriented method [CD94]. That is, the same notation may be used for three perspectives and types of models (Figure 1.6):